/* ***** BEGIN LICENSE BLOCK *****
 * Version: MPL 1.1/GPL 2.0/LGPL 2.1
 *
 * The contents of this file are subject to the Mozilla Public License Version
 * 1.1 (the "License"); you may not use this file except in compliance with
 * the License. You may obtain a copy of the License at
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 *
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 * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
 * for the specific language governing rights and limitations under the
 * License.
 *
 * The Original Code is part of dcm4che, an implementation of DICOM(TM) in
 * Java(TM), available at http://sourceforge.net/projects/dcm4che.
 *
 * The Initial Developer of the Original Code is
 * Agfa-Gevaert Group.
 * Portions created by the Initial Developer are Copyright (C) 2003-2005
 * the Initial Developer. All Rights Reserved.
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package org.dcm4chex.archive.mbean;

import java.io.File;
import java.util.Collections;
import java.util.HashMap;
import java.util.Map;

import javax.xml.transform.Templates;
import javax.xml.transform.TransformerFactory;
import javax.xml.transform.stream.StreamSource;

import org.dcm4chex.archive.util.FileUtils;
import org.jboss.system.ServiceMBeanSupport;

/**
 * @author Gunter Zeilinger <gunterze@gmail.com>
 * @version $Revision: 3309 $ $Date: 2007-05-06 20:38:48 -0300 (Sun, 06 May 2007) $
 * @since May 2, 2007
 */
public class TemplatesService extends ServiceMBeanSupport {
    
    private static final class CacheEntry {
        final Templates templates;
        final long lastModified;
        CacheEntry(Templates templates, long lastModified) {
            this.templates = templates;
            this.lastModified = lastModified;
        }
    }
    
    private final Map cache = Collections.synchronizedMap(new HashMap());
    
    public Templates getTemplates(File f) {
        long lastModified = f.lastModified();
        if (lastModified == 0L) { // file does not exist
            return null;
        }
        CacheEntry entry = (CacheEntry) cache.get(f);
        if (entry != null && entry.lastModified == lastModified) {
            return entry.templates;
        }
        try {
            log.info("Compiling Stylesheet " + f);
            Templates templates = TransformerFactory.newInstance()
                    .newTemplates(new StreamSource(f));
            cache.put(f, new CacheEntry(templates, lastModified));
            return templates;
        } catch (Exception e) {
            log.error("Compiling Stylesheet " + f + " failed:", e);
            return null;
        }        
    }

    public Templates getTemplatesForAET(String dir, String aet, String fname) {
        return getTemplates(getFile(dir, aet, fname));
    }

    private File getFile(String dir, String aet, String fname) {
        if (aet != null) {
            File f =  FileUtils.resolve(new File(new File(dir, aet), fname));
            if (f.exists()) {
                return f;
            }
        }
        return FileUtils.resolve(new File(dir, fname));
    }

    public void clearCache() {
        cache.clear();
    }
}
